Locking device



Nov. 15, 1927. Y 1,648,886

R. o. ALLEN LOCKING DEVICE 5 Filed Sep1fi8, 1925 I INVENTOR.

///S ATTO EY Patented Nov. 15, 1927.

UNITED STATES 1,648,886 PATENT "OFFICE.

ROY O. ALLEN, OF ATHENS, PENNSYLVANIA, ASSIGNOR T0 INGERSOLL-RAND COM- PANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

LOCKING DEVICE.

Application filed September 28, 1926. Serial No. 138,319.

This invention relates to pneumatic tools, but more particularly to a locking device for tools of the type in which the casing parts are secured together by means of screw threads.

The objects of the invention are to maintain a tight connection between the cas ng parts of pneumatic tools such as'chipping hammers, riveters and the like, and to enable such connection to be conveniently and effectively tightened whenever it becomes loosened through wear, vibration and other well known causes.

Other objects will appear hereinafter.

The invention consists of the combination of elements and arrangement of parts having the general mode of operation substantially as hereinafter described and claimed in the following specificationand illustrated in the accompanying drawings, in which Figure 1 is a sectional elevation of a pneumatic tool equipped with a locking device constructed in accordance with the practice of the invention, and

Figure 2 is a transverse view taken through Figure 1 on the line 2-2 looking in the direction of the arrows.

Referring to the drawings, the invention is shown embodied in a chipping hammer designated generally by A and having a cylinder B provided with a reciprocatory hammer piston C for delivering blows of impact to a chisel D supported in the front end of the cylinder. In this instance, a bushing E is disposed in the front end of the cylinder to act as a renewable guiding surface for the chisel. The rearward end of the cylinder B is provided with a recess F for the reception of a valve chest G in which may be arranged a distributing valve (not shown) of any suitable type for controlling the distribution of pressure fluid to the ends of the cylinder, passages H and J being provided for conveying such pressure fluid to the front and rearward ends respectively of the cylinder. i

The rearward end of the cylinder B i preferably of somewhat larger diameter than the main body portion of the cylinder and is provided with screw threads K which cooperate with corresponding screw-threads L of a hood 0 which is seated on the rearward end of the cylinder and presses against the valve chest G for holding said valve ,jected to severe vibration in usage.

chest firmly in position. A handle P car ried by the hood 0 is provided with a passage Q for conveying pressure fluid to the valve chest G. Such pressure fluid may be conveyed to a connection R in the end of the handle by asuitable conduit (not shown) and the admission of such pressure fluid to the valve chest may be controlled by a suitable throttle valve, only the controlling lever S of which is shown. I

As is well known, tools of the type to which the present invention applies aresub- As a result it is at times difficult to maintain tight connections between the casing parts, such as the cylinder B and the hood 0, particularly where such parts are secured together by means of screw threads. The present invention is intended to overcome this. difficulty and to this end the cylinder B is provided with a plurality of longitudinal teeth T in its peripheral surface, preferably forwardly of the threads K to engage teeth U carried by a key V. The key V in this instance may reciprocate in a relatively wide slot W in the hood and hasa threaded aperture X therethrough.

In order to actuate the key V in one direction or the other for the purpose of tighteningor loosening the threaded connection be-' tween the hood and the cylinder, a bolt Y is extended through suitable lugs Z and I) carried by the hood 0 and has an intermediate threaded portion 0 which engages the threaded aperture X of the key V. The threaded portion a of the bolt is preferably of somewhat greater length than the width of the slot W so that in practice the key V mayhave a limitedrange of travel between the lugs Z and I). A nut d screwed on the end of the bolt Y acts against the side of the lug b and serves to hold the bolt Y against rotative movement with respect to the lugs and also to produce a certain clamping effect at the forward end of the hood O.

In practice, after the hood 0 has been screwed on the cylinder B in the usual mannor the key V may be placed in the slot WV and the bolt Y is then inserted in the lugs Z and b and in the key V. After the head of the bolt Y contacts with thelug Z the bolt will tend to draw the key V in the direction of the lug Z, and, since the key V is interlocked with the cylinder B, the pressure thus-applied to the bolt will tend to tighten the connection between the hood and the cylinder. After the bolt has been turned to a point where no further relative movement between the hood and the cylinder may be obtained the nut (Z may be screwed 0n the end of the bolt Y thereby holding the bolt Y against rotation in the lugs and also tending to draw the lugs Z and I) together.

I claim:

1. In a pneumatic tool, the combination of a cylinder having a threaded portion, teeth on the cylinder, a hood screwed on the threaded portion, means supported by the hood and reciprocable therein 'to engage the teeth for locking'the hood on the cylinder, and means for actuating the first said means with respect to the hood.

2. In a pneumatic tool, the combination of a cylinder having a threaded portion, longitudinal teeth on the cylinder, a hood screwed on the threaded portion, said hood having a'slot, a key in the slot having teeth to engage the teeth on the cylinder for pre venting relative movement between the hood and the cylinder, and a bolt in threaded engagement with the key for actuating said key with respect to the hood. I v

3. In a pneumatic tool, the'combination of a cylinder having a threaded portion,

longitudinal teeth on the cylinder forwardly of the threaded portion, a hood screwed on the threaded portion, said hood having a slot in its forward end, a key in the slot normally out of contact with the walls of said slot,

ROY O. ALLEN. 

